Well firstly it's not the discrepancy in his ability, but his (should-be-fatal) refusal to accept the game around him.
I also don't see a discrepancy between his island-self and his home self. He was pissed with his family because they kept pressuring him to do a job he didn't want to do.
And when he throws an Xbox controller in his room, he's not exactly expecting his mum to retaliate with a BIM either.